SC 13G 1 a413387.txt O'NEILL; 1-02 OMB APPROVAL ---------------------------- OMB Number: 3235-0145 Expires: October 31, 2002 Estimated average burden hours per response ... 14.90 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* MarkWest Hydrocarbon, Inc. -------------------------------------------------------- (Name of Issuer) Common Stock, par value $0.01 per share -------------------------------------------------------- (Title of Class of Securities) 570762104 -------------------------------------------------------- (CUSIP Number) January 2, 2002 -------------------------------------------------------- (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: |X| Rule 13d-1(b) |_| Rule 13d-1(c) |_| Rule 13d-1(d) * The remainder of this cover page shall be filled out for a reporting person's initial filing on this form with respect to the subject class of securities, and for any subsequent amendment containing information which would alter the disclosures provided in a prior cover page. The information required in the remainder of this cover page shall not be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange Act of 1934 ("Act") or otherwise subject to the liabilities of that Section of the Act but shall be subject to all other provisions of the Act (however, see the Notes). PERSONS WHO RESPOND TO THE COLLECTION OF INFORMATION CONTAINED IN THIS FORM ARE NOT REQUIRED TO RESPOND UNLESS THE FORM DISPLAYS A CURRENTLY VALID OMB CONTROL NUMBER. SEC 1745 (03-00) Page 1 of 7 pages Schedule 13G Page 2 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ ________________________________________________________________________________ 1. NAME OF REPORTING PERSONS I.R.S. IDENTIFICATION NO. OF ABOVE PERSONS (ENTITIES ONLY) Brian T. O'Neill ________________________________________________________________________________ 2. CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP* (a) [_] (b) [_] ________________________________________________________________________________ 3. SEC USE ONLY ________________________________________________________________________________ 4. CITIZENSHIP OR PLACE OF ORGANIZATION United States of America ________________________________________________________________________________ NUMBER OF 5. SOLE VOTING POWER SHARES 23,902.5 (shares held in 401(k) account) _________________________________________________________________ BENEFICIALLY 6. SHARED VOTING POWER OWNED BY 455,825** _________________________________________________________________ EACH 7. SOLE DISPOSITIVE POWER REPORTING 23,902.5 (shares held in 401(k) account) _________________________________________________________________ PERSON 8. SHARED DISPOSITIVE POWER WITH 455,825** ________________________________________________________________________________ 9. AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON 479,727.5 ________________________________________________________________________________ 10. CHECK BOX IF THE AGGREGATE AMOUNT IN ROW (9) EXCLUDES CERTAIN SHARES (SEE INSTRUCTIONS) N/A [_] ________________________________________________________________________________ 11. PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW 9 5.64% ________________________________________________________________________________ 12. TYPE OF REPORTING PERSON* IN ________________________________________________________________________________ ** As of January 2, 2002. Consists of (1) 409,475 shares owned directly by Mr. O'Neill and (2) 46,350 shares beneficially owned by Mr. O'Neill pursuant to currently exercisable options, or options exercisable within sixty days of January 2, 2002, granted to Brian O'Neill by MarkWest Hydrocarbon, Inc. under its employee stock option plan. Mr. O'Neill and his wife, Jennifer O'Neill, consolidated their holdings into a joint account in January 2002. Schedule 13G Page 3 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ Item 1. (a) Name of Issuer: MarkWest Hydrocarbon, Inc. (b) Address of Issuer's Principal Executive Offices: 155 Inverness Drive West, Suite 200 Englewood, Colorado 80112 Item 2. (a) Name of Persons Filing: Brian T. O'Neill (b) Address of Principal Business Office: c/o 155 Inverness Drive West, Suite 200 Englewood, Colorado 80112 (c) Citizenship: THE FILING PERSON'S CITIZENSHIP OR PLACE OF ORGANIZATION IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (d) Title of Class of Securities: common stock, par value $0.01 per share (e) CUSIP Number: 570762104 Item 3. If this statement is filed pursuant to Rule 13d-1(b), or 13d-2(b), check whether the person filing is a: (a) |_| Broker or dealer registered under section 15 of the Act (15 U.S.C. 78o). (b) |_| Bank as defined in section 3(a)(6) of the Act (15 U.S.C. 78c). (c) |_| Insurance company as defined in section 3(a)(19) of the Act (15 U.S.C. 78c). (d) |_| Investment company registered under section 8 of the Investment Company Act of 1940 (15 U.S.C. 80a-8). (e) |_| An investment adviser in accordance with Section 240.13d-1(b)(ii)(E). (f) |_| An employee benefit plan or endowment fund in accordance with Section 240.13d-1(b)(1)(ii)(F). Schedule 13G Page 3 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ (g) |_| A parent holding company or control person in accordance with Section 240.13d-1(b)(1)(ii)(G). (h) |_| A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act (12 U.S.C. 1813). (i) |_| A church plan that is excluded from the definition of an investment company under section 3(c)(14) of the Investment Company Act of 1940 (15 U.S.C. 80a-3). (j) |_| Group, in accordance with Section 240.13d-1(b)(1)(ii)(J). Item 4. Ownership (a) Amount Beneficially Owned: THE AMOUNT BENEFICIALLY OWNED BY THE FILING PERSON IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (b) Percent of Class: THE PERCENT OF CLASS BENEFICIALLY OWNED BY THE FILING PERSON IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (c) Number of shares as to which such persons have: (i) Sole power to vote or to direct the vote: THE NUMBER OF SHARES AS TO WHICH THE FILING PERSON HAS THE SOLE POWER TO VOTE OR TO DIRECT THE VOTE IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (ii) Shared power to vote or to direct the vote: THE NUMBER OF SHARES AS TO WHICH THE FILING PERSON HAS THE SHARED POWER TO VOTE OR TO DIRECT THE VOTE IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (iii) Sole power to dispose or to direct the disposition of: Schedule 13G Page 4 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ THE NUMBER OF SHARES AS TO WHICH THE FILING PERSON HAS THE SOLE POWER TO DISPOSE OR TO DIRECT THE DISPOSITION OF IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. (iv) Shared power to dispose or to direct the disposition of: THE NUMBER OF SHARES AS TO WHICH THE FILING PERSON HAS THE SHARED POWER TO DISPOSE OR TO DIRECT THE DISPOSITION OF IS SET FORTH ON THE COVER PAGE AND INCORPORATED BY REFERENCE HEREIN. Item 5. Ownership of Five Percent or Less of a Class: N/A If this statement is being filed to report the fact that as of the date hereof the reporting person has ceased to be the beneficial owner of more than five percent of the class of securities, check the following. Item 6. Ownership of More than Five Percent on Behalf of Another Person: N/A Item 7. Identification and Classification of the Subsidiary Which Acquired the Security Being Reported on By the Parent Holding Company: N/A Item 8. Identification and Classification of Members of the Group: N/A Item 9. Notice of Dissolution of Group: N/A Schedule 13G Page 6 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ Item 10. Certification: By signing below I certify that, to the best of my knowledge and belief, the securities referred to above were acquired and are held in the ordinary course of business and were not acquired and are not held for the purpose of or with the effect of changing or influencing the control of the issuer of the securities and were not acquired and are not held in connection with or as a participant in any transaction having that purpose or effect. Schedule 13G Page 7 of 7 pages CUSIP No. 570762104 MarkWest Hydrocarbon, Inc. ________________________________________________________________________________ SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. 1/10/02 ------------------------------------- /S/BRIAN T. O'NEILL ------------------------------------- Signature BRIAN T. O'NEILL ------------------------------------- Name